Hiram stevens maxim



. H. s. MAXIM.

REGOVERING SOLVENTS FROMEXPLOSIVES.

No. 430,215. Patented June 17 1890.

UNITED STATES HIRAH STEVENS MAXIM, OF LONDON, ENGLAND.

RECOVERING SOLVENTS FROM EXPLOSIVES.

SPECIFICATION forming part of Letters Patent No. 430,215, dated June 17,1890.

Application filed March 4, 1890. serial No. 342,644. (No model.)Patented in England December 20, 1888, No.18,663.

To all whom it Hwy concern.-

Be it known that I, HIRAM STEvENs MAXIM, mechanical engineer, a citizenof the United States, and a residentof London, England, have inventednew and useful Improvements Relating to the Manufacture of Explosivesand to Apparatus therefor, (for which Ihave obtained a patentin GreatBritain, No. 18,663, bearing dateDecembei-20, 1888,) of which thefollowing is a specification, reference being had to the accompanyingdrawing.

My invention relates to the manufacture of explosives and to apparatustherefor.

In the production of explosive material by the treatment of gunscottonwith a solvent such as acetone, ethylic acetate, ether, or thelike-considerable loss of the solvent generally occurs in the drying ofthe'product, thus generally enhancing the cost of manufacture of theexplosive material.

The object of my present invention is to provide for the recovery of thewhole or nearly the whole of the solvents used in the manufacture ofsuch explosive material, and which in the drying of the said explosivematerial as heretofore practiced are evaporated and lost; and my saidinvention comprises an improved method of treating the pyroxyline ordissolved gun-cotton for this purpose.

My said invention also comprises improved apparatushereinafterdescribed.

According to my method of recovering the said solvents, I cause heatedair or other gas to pass over or in contact with the surface of thedissolved gun-cotton in a drying-chamber or evaporator, so that as thesolvents are evaporated they are taken up or absorbed by the air orother gas, and I then conduct the air or other gas carrying thevolatilized solvents to a cold chamber or condenser, in which the saidsolvents condense and from which they may be drawn off in a liquidstate. I then reheat the air or other gas passing from the cold chamberand again cause it to pass through the drying-chamber or evaporator, theair or other gas being thus caused to circulate continuously through theentire apparatus.

I have shown in vertical longitudinal central section in theaccompanying drawing the apparatus for carrying out this invention.

A is the drying-chamber or evaporator, in

which are arranged a series of pans or trays B B of any suitable shape,and preferably arranged as shown-that is to say, the said pans B B arearranged one above another and extend alternately from either side orend of the chamber A to within a short distance from the opposite sideor end thereof, so that the air and vaporpassing through the saidchamber must follow a circuitous path.

0 is the cold chamber or condenser, with which the upper end of thedrying-chamber or evaporator A is connected by pipes D D for the passageof the vaporized solvents. The cold chamber or condenserO is connectedby a pipe E with a heater F, for heating the air during its return tothe drying or evaporating chamber-A, with the lower end of which thesaid heater is connected by a pipe G. The cold chamber 0 is placed in atank or vessel H, through which water or other cooling-liquid is causedto flow. The said cold chamber is provided with a discharge-pipe J,having a stop-cock J, beneath which a bottle or other receptacle K maybe placed for the reception of the liquid solvent discharged from thesaid chamber. A fan-blower L, or other suitable apparatus, is providedfor causing the continuous circulation of the air through thedryingchamber, the cold chamber or condenser, and the heater.

A small pipe a, is provided above each of the pans B B, for theintroduction of the pyroXyline or explosive material into the said pans.These pipes a may communicate with a larger pipe or main, suitable cocksbeing provided where necessary. The cold chamber or condenser O ispreferably constructed with a series of small tubes 0 to increase thearea or amount of cooling-surface.

T -e-operation of the apparatus above described is as follows, viz: Thepans or trays B B being charged with pyroxyline, the fan L is startedand the air circulated through the apparatus. The air is warmed in passing through the heater F and ascends between the pans B B in thedrying-chamber or evaporator A, and absorbs or takes up a large quantityof the vapor of the solvent or solvents contained in the said pans. Theair is then discharged into the cold chamber 0, wherein the solventscondense and fall into the bottle or receptacle K.

The air freed from the vaporized solvents is again passed through theheater F and evaporator A, and so on. By the operation above describedthe whole or nearly the whole of the solvent or solvents which wouldotherwise be lost is recovered. The said solvent or solvents may thus beused and recovered a great number of times.

One great advantage arising from the employment of acurrent of heatedair, as above described, is that the evaporation proceeds Without theformation of bubbles, such as would be formed if the material weredirectly heated sufliciently to cause the solvent or solvents toevaporate at the normal pressure of the atmosphere.

I sometimes provide, in combination with the pipe G, one or morechambers M, containing hygroscopic material-such as calciumchloridethrough which the air will pass in its circulation through theapparatus, and whereby all the aqueous vapor will be removed from theair, so that the liquid which falls into the bottle or other receptacleK will be free from water, and the explosive material which is beingdried will not undergo any change such as having its surface whitened-asis the case when dried in presence of moisture, but will be transparentand very homogeneous.

The pans or trays in the chamber A are removable. They are preferablyarranged in such a manner that they may be lifted out all together. Iprefer to make the pans, or, at least, the bottoms of the same, of glassor similar material.

The drying-chamber or evaporator A and the heater F should be inclosedin casings of Wood or other suitable material, as shown, The heater F isprovided with acoil F, through which steam, hot Water, or other heatingmedium is to be passed.

WVhat I claim is The herein-described method of recovering solvents usedin the manufacture of explosive material, which consists in exposing thedissolved material in receptacles in a dryingchamber or evaporator andmaintaining a constant circulation of air or gas through saidevaporator, and acondensing-chamber in communication therewith, heatingsaid air or gas before it enters the evaporator, as set forth.

In testimony whereof I havehereunto signed my name in the presence oftwo subscribing witnesses.

I-IIRAM STEVENS MAXIM Witnesses:

DAVID YOUNG, CHAS. B. BURDON.

